The LWR is a difficult case for xenon poisoning (compared to other reactors) because of the thermal spectrum and the lack of homogenization (it's not just a temporal problem but a spatial problem) but if you add reactivity swing it can be managed. It's a problem for going from 0-100% quickly but not a problem for following loads across the day, see

https://www.oecd-nea.org/upload/docs/application/pdf/2021-12...